Evolution of a user interface, before you see it: why tabs are taking over the world

"At some point you have to be the benevolent
dictator
developer," notes Gus Mueller, developer of Voodoopad (which is a Mac OSX shareware product that is sort-of a DIY wiki, or todo list, or web content controller, or - in my own case - section planner).

In an interesting post, once you follow the links to the (not inline) images, he explains how he moved from the previous version to the latest, which uses tabs. You know, like browsers, and the new version of Office, and (it is rumoured - though so far it's all just fakery) the next version of the OSX Finder.

Early on my goal was to make VoodooPad 3 like one of the iApps with blue source lists on the left ala iTunes or iPhoto. I also really wanted tabs. And a 3d fly view with all the connections between the pages. And a pony. At least we got tabs.

However life for an independent developer trying to guess what things are going to look like in a version of the operating system that won't even be previewed until August, but which will influence the look of everything that runs on it, also had to be considered:

At some point I decided that the dark windows you see in iTunes are going to be the way things are done in Leopard, and if I didn't adopt it now then VP3 would look dated when it came out (see what you're doing to us Apple?! Why am I wasting time thinking about future window styles?).

The best way to see the evolution of Mueller's thinking about the interface is to open the various links to the images from his post, and tab quickly between them. Which is better? Which is best?

One thing that I think is becoming clearer, as we start to spawn multiple documents while reading a parent one (eg clicking links in a web document that are opened in separate tabs), is that the "multiple window" method that worked well in early versions of the Mac OS just doesn't anymore. Right now, I've got more than 50 windows open (from 21 visible applications); but that's not close to the number of "documents" that are open, because three of those windows are my browser, and each of those windows has more than 10 tabs open. That means that I've got nearly 80 document windows available.

Having those sorted using a single window for each document just won't work. You have to have tabs, or the level of complexity becomes befuddling. It's hard enough as it is. (And OSX tweaks like Exposé don't help very much; mentally, I tend to organise what's in a window, and what I'm working on, by application. Exposé just puts all the windows randomly around the screen, not organised by application, so it becomes a game of hide-and-seek to find the one you want. Far quicker just to switch application.)

This profusion of windows does mean, I'd suggest, that gradually, more and more applications that used to offer multiple windows as their basic way of working (including VoodooPad) are moving towards tabs. Browsers first; iTunes already does; Office (the PC version) is doing something like it; and I think that it's pretty obvious that it would be smart for Apple to implement this in the "Leopard" version of Finder, because it would stop one having dozens of those Finder windows cluttering up the desktop.

It would mean a single window for each application - a victory for the Multiple Document Interface over the Single Document Interface. (The MDI does create problems when you want to drag something from one tab to another, but for that you can always open another window. And the example used at that Wikipedia link for the MDI is possibly the most confusing possible. Think of it this way: a single browser window with multiple tabs is an example of an MDI.)

Is that good, or bad? Well, if it means we can find what we want when we want it, it has to be better. Oddly though the development of tabs is going hand-in-hand with the growth of search technologies like Google Desktop Search, Apple's Spotlight, and so on. Too many windows too handle easily; too much information to find easily.